Endotoxin (i.e. lipopolysaccharide, LPS) is the major pathogenic factor of gram-negative septic shock. Endotoxin-induced shock and death may be associated with host overproduction of tumor necrosis factor alpha. In the search for new anti-endotoxin molecules, we studied the endotoxin-neutralizing capacity of a human lactoferrin-derived 33-mer synthetic peptide (GRRRRSVQWCAVSQPEATKCFQWQ-RNMRKVRGP, LF-33) and the results were published in the first refernce below. We also studied the immunostimulatory effects of meningococcal LPS that is tightly associated with outer-membrane proteins (OMP) and undissociable from OMP by sodium deoxycholate treatment. The toxicities of the LPS were greatly reduced when it is tightly associated with the OMP. Immunization of mice with the OMP-associated LPS protected them against experimental meningococcal infection and septic shock. The results have been accepted for publiction. No new research was carried out in this fiscal year due to lacking of manpower, but accumulated results have been published.